Art of converting oil



July 26, 1932; F. A. HOWARD E'rAL I 1,369,337

ART QF CONVERTING' OIL Filed lay 23. 1921 Patented July 26, 1932 UNITED STATES FRANK A. HOWARD AND NATHANIEL E. LOOMIS,

PATENT o FElcE OF ELIZABETH, NEW JERSEY, ASSIGN- ORS, BY MESNE ASSIGNMENTS, TO GASOLINE PRODUCTS COMPANY, INC., F NEWARK, NEW JERSEY, A CORPORATION OF DELAWARE ART OF CONVERTIN G OIL Application led May 23, 1921, Serial No. 471,736, and in the Netherlands .Tanuary 12, 1921.

The present invention relates to the art of converting hydrocarbon oils and more particularly to the reduction of the density and viscosity of heavier hydrocarbon oils and to the formation of low boiling point hydrocarbon oils therefrom. It will be clearly understood from the following description of a specific embodiment thereof, illustrated by the accompanying drawing, in which Fig. 1 is a diagrammatic view, partly in elevation and partly in section, of means for carrying out the invention, and

Fig. 2 is a plan view of the converting devices.

Referring more particularly to the dra-wing, the numeral 5 indicates a. pump, by which the oil to be treated is forced under pressure through pipe 6 into preheater 7 g where it may be preheated by indirect heat lexchange as more fully hereinafter described.

From the preheater 7 the oil passes through pipes 8 and 9, both of which are preferably lagged, into the initial heating coil 10. Steam may be admitted into the coil through pipe 11. The initial heating coil 10 may suitably be constructed of a plurality of longitudinal capped tubes 12 connected near their ends by cross tubes 13. From the initial heating coil 10 the oil passes through pipe 14, preferably lagged, to the converting coil 15, of similar construction to the coil 10. From convert` ing coil 15 the oil passes through pipe 16 to the preheater 7, where it enters the central chamber 17 and surrounds the tubes 18 through which the incoming stock is passing. In passing through preheater 7 the converted oil is cooled. The cooled oil issues from preheater 7 through pipe 19. in which an expansion valve 20 is provided. whereby the pressure in the oil is partially or whollyl relieved. The oil then .flows into drum 21 above balile 22. and the vapors and gases are then liberated from the liquid oil. which may be removed through discharge pipe 23. v The gases and vapors issuing from the drum 21 pass through pipe 24 to condenser 25. from which the condensate and the uncondensed gases and vapors pass into receiver 26. This receiver is provided with an inverted conical bottom, into which the condensed water preheating and settles and from which it may be withdrawn through pipe 27. The oil condensate (gasoline, for example) may bie' withdrawn through pipe 28. The uncondensed gases and vapors may escape through pipe 29. The pressure maintained upon the oil during its passage through the initial heating and conducevits viscosity and to produce lighter hy-` drocarbons therefrom. A heavyl Mexican crude oil' of about 12.5 B.- gravity, 120F. flash point and a viscosity of about 800 Saybolt 210 F. is pumped under pressure of 60 pounds gauge or higher through the preheater and the initial heating and converting coils. In the preheater 7 its temperature is raised to a point somewhat below that at which cracking takes place to an appreciable extent, say about 4150-500" F., at which temperature the oil enters the initial heating coil 10. A small proportion of superheated steam, for example 7 to 9 per cent. by Weight of the oil, is introduced into the oil through pire 11 as the oil ente-rs the initial heating co1 As the oil Hows through the initial heating coil 10 the latter is fired hard in order to rapidly raise the temperature of the oil to a temperature at whichl 'conversion or cracking proceeds at a substantial rate, which temperature is above 650 F. and is preferably 7 25 -7 50 F., this temperature being acquired 'as the oil approaches the end of the initial heating coil. From the initial heating coil 10 the oil passes at once into the converting coil 15.. This coil is fired slowly, the temperature rising only slightly to a higher cracking or conversion temperature of say 800 F. and being' maintained there. During its travel through this coilthe desired conversion of the oil is effected and local overheating of the coil is minimized. This coil, lin the type and the steam will be in the vapor phase after reduction of the pressure on the oil. If desired or necessary, an auxiliary cooling device may be employed to aid in cooling the converted oil. The cooled oil leaving the preheater passes through expansion valve 20 in pipe 19 to the expansion drum, which may be maintained under atmospheric pressure or if desired under a slight pressure of,`say, 10 pounds, to assist in the expulsion of its liquid contents. n

On entering thedrum 21 the light hydrocarbons formed in the conversion process and the steam are evolved as vapors, passing out through pipe 24, and the liquid products accumulate and may be withdrawn or expelled through discharge pipe 23. The temperature trio which the converted oil has been cooled (C300-325 F.) is such that these liquid products have a flash point of 150 F. or above. The vapors and gases issuing through pipe 24 pass through condenser 25, in which their gasoline constituents and the steam present are condensed. The condensate and uncondensed gases and vapors pass on to receptacle 26 where the water and gasoline collect and are separatedv while the gases and vapors pass out through pipe 29 to a suitable holder. In the example given about 10 per cent. of distillate is formed and the converted oil has adensity of about 14 B. and a viscosity of approximately 225 at 212 F. and may be. directly utilized as a fuel oil.

The temperature to which the converted oil is reduced before it. enters the expansion Y 'drum may be varied in accordance with the desired characteristics of the converted oil product. Thus, if cooled to 225 F., the steam will be expelled and a liquid product of lower iash point and viscosity described will be produced. Or, if desired, the converted oil may be entirely cooled before pressure is released, and subsequently distilled to remove the light hydrocarbons. It is furthermore apparent that the process may be applied to other hydrocarbon oils and particularly to the heavy bottoms obtained in the ordinary! reduction of such y crudes as lightl Mexican crude, California crude or Mid-Continent crude.

It is found that by the procedure described, in which the oil is rapidly raised to a cracking temperature and subsequently its temperature slowly raisedto and maintained at a high cracking temperature by slow firnot to be regarded as than above ing, the production of coke is materially reduced or even substantially eliminated.

The preheating drum 7 may, if desired, be `eliminated entirely, or another type of preheaterv substituted. Furthermore suitable pressure relieving devices may be inserted between the preheater and the coil or elsewhere as vdesired in case of plugging or stoppage in the coils, and back pressure may be guarded lagainst by the employment of check valvesl at suitable points.

Although the invention has been descrlbed in connection with certain details of process and apparatus incidental to the treatment of a certain oil for a certain purpose, these are intended to be illustrative only and are limitations upon the scope of the invention, except in so far as 1ncluded in the accompanying claims.

We claim:

1. In the process of effecting the pyrogenetic conversion of a heavy hydrocarbon oil, continuously moving a body of said oil in succession, `first through a heating zone in which the oil is raised rapidly to a temperature at which cracking takes place at a substantial rate, and thereupon, w1t-h undiminished velocity and without substantial separation of vapors through and out of a zone, in which it is heated slowly to maintain its cracking temperature while maintaining pressure on the oil suicient to maintain it substantially in the liquid phase.

2. In the process of eii'ecting the pyrogenetic conversion of a heavy hydrocarbon oil, irst heating the said oil in a continuously flowing stream having undiminished velocity to a temperature below that at which appreciable cracking takes place, then supplying heat rapidly to the oil to bring it to an elevated cracking temperature and subsequently applying heat slowly to the oil to maintain it at an elevated cracking temperature while maintaining pressure on the oil sufficient to maintain it substantially in the liquid phase.

3. In the process of eecting the pyrogenetc conversion of heavy hydrocarbon oil, irst heating the said oil in a continuously flowing stream to a temperature below that at which appreciable cracking takes place, then admixing a small proportion of steam therewith, supplying heat rapidly to the oil to bring it to an elevated cracking temperature and subsequently applying heat slowly to the oil while flowing with undiminished velocity to maintain it at an elevated cracking temperature while maintaining pressure on the oil suiiicient to maintain Iit substantially in the liquid phase.

4. In the process of eifecting the pyrogenetic conversion of a heavy hydrocarbon oil, first heating the said oil in a continuously flowing stream to a temperature below that then supplying heat rapidly -to the oil to bring it to an elevated cracking temperature .and subsequently applying heat slowly to thel oil while flowing with undiminished velocity to maintain it at an elevated cracking tem-- perature While maintaining pressure on the oil sufficient to hold it substantially in the liquid phase and utilizing the contained heat the oil in a continuous stream, first heating,

the flowing oil stream to a temperature below that at which appreciable cracking takes place, then supplyin heat rapidly to the flowing oil stream toy ring it to an elevated.

cracking temperature, subsequently applying heat slowly to the flowing oil stream while owing with undiminished velocity to maintain it at an elevated cracking temperature and maintaining pressure on the oil stream suiicient to maintain the oil substantially in the liquid state. .c i

6. The process of effecting the pyrogenetic conversion of a heavy hydrocarbon oil which consists in continuously moving a body of oil in succession first through a heating zone in which the oil is raised rapidly to a temperature at which cracking takes place at a substantial rate, and thereupon and at substantially the same rate of speed through a zone in which it is mildly heated to maintain its cracking temperature and without substantial separation of vapors, pressure being maintained upon the oil suiicient to maintain it substantially in the liquid phase.

7 The process of effecting the pyrogenetio conversion of a heavy hydrocarbon oil into lighter hydrocarbon oils which consists in flowing the heavy oil in a restricted stream at high velocity through an initial heating zone in which it is heated rapidly to a cracking temperature above 650 F. and thereupon fiowing the initially heated oil without substantial separation of vapors'and at substantially the same rate of speed once only through and out of a zone, supplying heat at a slow rate therein sufficient to maintain the said temperature without more than a slight rise in temperature while maintaining a pressure of at least 60 pounds gauge on the oil in both said zones.

8. In the process of effecting the pyrogenetic conversion of a heavy hydrocarbon oil, continuously moving a body of said oil in a restricted stream at high velocity in succession, first through a heating zone in which the oil is raised rapidly to a temperature at which cracking takes place at a substantial rate, and thereupon without substantial separation of vapors and with undiminished velocity once lonly through and out of a zone in which it is heated slowly to maintain its cracking temperature without more than a slight rise in temperature while maintaining a pressure of at least 60 pounds gauge on the oil in both zones.

9. The process of effecting the pyrogenetic conversionv of a hydrocarbon oil into desired lower boiling products which comprises continuously forcing a stream of said oil at high velocity in succession, first through a restricted passage in a heating zone in which the oil is raised rapidly to a temperature at which cracking takes place at a substantial rate, and thereupon with undiminished velocity in a restricted stream once only through and out of a zone in which it is heated mildly without substantial separation of vapors to maintain its cracking tem-perature without more than a slight rise in temperature, discharging the heated oil products from the latter L'zone and maintaining superatmospheric pressure on the oil stream passing through said heating zones, whereby substantial conversion into desired lower boiling products is secured in said latter zone.

10. In the process of effecting the pyrogenetic conversion of a hydrocarbon oil into desired lower boiling hydrocarbon oils, continuously moving a body of said oil in a stream at high velocity in succession, first through a restricted passage -in a heating zone in which the oil is raised rapidly to a temperature at which i cracking takes place at a substantial rate and `thereupon with undiminished velocity once' only through and out of a zone in which it is heated mildly without substantial separation of vapors to maintain its cracking temperature without more than a slight rise in temperature, discharging the heated oil products from the latter zone while maintaining superatmospheric pressure on the oil in said stream passing through said heating zones whereby f substantial conversion thereof into desired 4low boiling products in said latter heating zone is secured, and utilizing the contained heat of the treated oil to effect the preheating of fresh oil passing to said heated zones.

1 1. In the process of effecting the pyrogenetic conversion of a hydrocarbon oil, continuously moving a body of said oil in a restricted stream at high velocity in succession, first through a heating zone in which the oil is raised rapidly to a temperature at which cracking takes place at a substantial rate, and

thereupon with undiminished'velocity once only through and out of the zone in which it is heated slowly without substantial separa tion of vapors to maintain its cracking temperature while maintaining a pressure of at least 60 lbs. gauge on the oil in both zones, and utilizing the contained heat of the treated oil to effect the preheating of fresh .oil pass ing to said heating zones.

12. In the process of effecting the pyrogenetic conversion of a hydrocarbon oil, forcing sa1d oil in a restricted stream through a continuous co1l 41n Whlch 1t 1s sub]ected to a heating means to effect rapid heating of the oil in flow through the coil to a cracking temperature, passing the oil leaving said coil at undiminished velocity once only through and out of a coil in which it is subjected to a second heating means by which mild heating of the oil passing through said coil is effected to maintain it at a cracking temperature Withoutl more than a slight rise in temperature, and maintaining superatlnospheric pressure on the oil stream passing through the coils in Said heating chambers.

FRANK A. HOWARD.

NATHANIEL E. LOOMIS. 

